It is well-known that center-pivot vehicles have the advantage of being extremely maneuverable. Other advantages of center-pivot vehicles include exact steering geometries, rear wheels tract with front wheels, tighter turning radius over common axle pivot steering, and the ability to move the forward and rearward sections even if the vehicle is not moving.
Typically, center-pivot vehicles have forward and rearward sections hinged together. Articulation of the sections is often provided by one or more hydraulic cylinders. For example, one cylinder on one side of the hinge expands while another cylinder on the opposite side of the hinge contracts for articulating the forward section relative to the rearward section for turning the vehicle.
Current systems for providing center-pivoting of a vehicle are bulky, have limited operating parameters, require an excessive amount of power to operate, and are expensive to build and to operate. Because of the interlinking between the forward and rearward sections, this type of center-pivot system limits the operating independency of the forward and rearward sections, which in turn limits the stability of these sections and the amount each is able to pitch and roll relative to the other. Invariably, the ability of the forward and rearward sections of a center-pivot vehicle to pitch and roll freely is retarded by the structure or functionality providing center-pivoting.
Therefore, it is a primary object, feature or advantage of the present invention to improve over the state of the art.
It is a further object, feature or advantage of the present invention to provide an apparatus and method for a center-pivot steering articulated vehicle wherein the system providing articulation is non-bulky, inexpensive to build, operate and maintain.
Yet another object, feature or advantage of the present invention is to provide an apparatus and method for a center-pivot steering articulated vehicle wherein the system providing articulation has limited moving parts interlinking forward and rearward sections of the vehicle.
A further object, feature or advantage of the present invention is to provide an apparatus and method for a center-pivot steering articulated vehicle wherein the system providing articulation has a minimal power requirement.
Another object, feature or advantage of the present invention is to provide an apparatus and method for a center-pivot steering articulated vehicle wherein the system providing articulation provides operating independency of forward and rearward sections for increased stability, tracking, and handling.
Yet another object, feature or advantage of the present invention is to provide an apparatus and method for a center-pivot steering articulated vehicle wherein the system providing articulation allows for forward and rearward section dependency whereby both sections remain solidly grounded and true to the terrain regardless of the terrain.
A further object, feature or advantage of the present invention is to provide an apparatus and method for a center-pivot steering articulated vehicle wherein the pitch and roll of the forward and rearward sections are independent of articulation of the forward and rearward sections.
Another object, feature or advantage of the present invention is to provide an apparatus and method for a center-pivot steering articulated vehicle wherein the system providing articulation is a single self-contained unit for simplicity, cost savings and ease of operation and troubleshooting.
U.S. Pat. No. 6,273,435 shows a trailer with a non-tilting moveable bed. This trailer includes a hydraulic cylinder which is connected to a linkage between a base and bed frame. Extension of the hydraulic cylinder causes the linkage to articulate and causes movement of the bed frame relative to the base frame. The bed frame is guided in a series of tracks between an elevated position and a lowered position.
The device of U.S. Pat. No. 6,273,435 has the disadvantage of requiring a complicated mechanical linkage between a hydraulic cylinder bed frame and the base frame. Furthermore, the hydraulic cylinder rises and powers in unison with the bed frame, rather than being stationary relative to the base frame. The bed frame is also limited in that it's non-tilting.
Therefore a primary object of the present invention is to provide a vehicle having load lifting bed moveable generally vertically between trailing and loading positions relative to the bed frame.
A further objective of the present invention is to provide a load lifting bed that is tiltable between loading and dumping positions relative to the bed frame.
A further objective of the present invention is to provide a vehicle with a load lifting bed which can be maintained in a horizontal position while moved between trailing and loading positions for easy loading and unloading of machinery or other objects being transported by the vehicle.
A still further objective of the present invention is to provide a vehicle with a load lifting bed that can be tilted from the horizontal position in either the trailing or loading position or any location of the bed therebetween.
A still further objective of the present invention is to provide a vehicle with a load lifting bed which uses a simple mechanism for moving the bed between trailing and loading positions having a new, safe design.
The means and method of accomplishing these and other objectives will become apparent in the following description of the invention.